Treatment of solvent refined oils with adsorbents



Patented June 10, 1941 UNITED STATES PATENT 2,245,016 OF F l CE TREATMENT OF SOLVENT REFINED OILS WITH ADSORBENTS No Drawing. Application May 25, 1939, Serial No. 275,673.

12 Claims. This invention relates to a method 01' attaining a higher efllciency in the treating of solventrefined oils with solid adsorbent filtering materials. The invention particularly relates to a method of treating solvent refined oils with solid adsorbent materials of increased activity and useful life.

Practically all petroleum products require some refining to produce a marketable product. In former years the refining of heavy oils such as the lubricating oils almost universally comprised a sulfuric acid treatment for removing undesirable components. Of late years a considerable amount of the sulfuric acid treating of lubricating oils has been eliminated by the advent of solvent refining. In these well known solvent refining processes the solvents make preferential selections of the desired components. However whether the oils are subjected to sulfuric acid treatment or to solvent refining or both it is common practice to pass the oils through a further refining treatment wherein they are contacted with solid adsorbent materials such as clays. The clays serve principally to improve the color of the oil but may also perform additional refining actions. In the usual practice today the oil or oil with added diluent is percolated through granules of the clay. Our present invention is concerned with the treatment of oilswhich have been solvent refined as distinguished from the treatment of oils which have been only acid-treated.

In general three different methods are used for refining petroleum oils with clays. These methods are the percolation process wherein liquid oil is percolated through granules of the clay, the contact process wherein liquid oil is contacted with finely pulverized clay and the vaporprocess wherein oil vapors are passed through granules of the clay. Usually the clays used in vapor processes are transferred to percolation processes after one use and the contact clays are usually discarded after one use.

As may well be appreciated enormous quanti ties of clays are used throughout the petroleum industry. After the clays have refined a certain amount of oil they become so contaminated with carbonaceous impurities collected from the oil that they must be regenerated or discarded. Heretofore this regeneration has been effected principally by a chemical combustion which universally consists of burning oil the impurities.

In the past various methods have been used for carrying out the burning of granular spent clay. One of the first comprised spreading the clay on an open hearth and burning it. Today there are three principal methods in general use.

In the first method the clay falls or cascades over bafiles' set at about a 45 angle through a flue countercurrent to gases of combustion. In

the secondmethod the clay is regenerated in a rotary kiln slightly inclined from the horizontal.

In the third method, which probably is the most commonly used, multiple hearth burners are employed. These multiple hearth furnaces or burners are substantially the same as used in the roasting of ore and are of either the Nichols- Herreshoff or Wedge type. In these burners the clay is slowly rabbled across each hearth, dropping from one to another until the bottom hearth is reached. In all of these conventionally used methods there is a progressive degradation in the efficiency oi the clay with each burning and finally the clay must be discarded to waste since it is no longer capable of being regenerated sufflciently to warrant further treatment.

The two co-pending applications Serial Num ber 210,150, filed May 26, 1938, and Serial Number 270,943, filed April 29, 1939, of John W. Payne disclose and claim two other methods adapted for regenerating clay.

Since clays which have had a different number oi burnings by the present conventional processes have different efficiencies, they are kept separate and separately classified. In some of the larger refineries extensive inventories and bin facilities are required in order to maintain the clays according to their classification or efliciency. Not only do the large inventories of clay, bin facilities, etc. mean added expense but quite obviously the successive degradation in eificiency and the corresponding requirement of more clay increases the expense.

Most important amongst the disadvantages of the commonly used clay regeneration methods, however, is the fact the clay can only be regenerated a very limited number of times before its efiiciency is so low that it does not pay to regenerate it, at which time the clay is thrown away to waste. In general granular petroleum filter clays are only regenerated seven or eight times and practically never more than ten or fifteen times at which time their efiiciency is reduced to about 50% of the original and they are thrown away. As stated above, the finely pulverized contact clays. e. g., 200 mesh or finer, are usually never regenerated.

In o der to further stress the tremendous importance of the problem involved it might be refinery in the country has large dumps of spent clays that have been thrown away to complete waste. In some cases this waste clay is left as conclusive that other a dump and in other cases it is used for filling in low land, sold for fertilizer, etc. However, in all cases there is this enormous discarding of spent clays. Such waste is accepted as a necessary evil of the process. I

There have been a few suggestions from time to time in other fields that clays might be regenerated to higher eificiency. Likewise in the petroleum industry it has been suggested that a particular form of clay under very special conditions might be regenerated to higher efficiency. However, the fact other methods have not been taken up by the petroleum industry is believed known regeneration processes than those now used are not feasible for treatment oi the clays used in refining petroleum or it is not obvious that they couldoe applied to regenerating petroleum clays. While such a fact is not usually so conclusive it is believed to be in the present case in view of the tremendous amounts of clay used and thrown away to waste each year as shown above and the increased amounts necessary because of the successive losses in efilciency as well as other attending disadvantages. Certainly it cannot be maintained that one of the country's largest industries would go on year after year suilering the'above-mentioned wastes and disadvantages i! a remedy therefor was obvious.

It is an object of our invention to provide an improved method of treating solvent refined petroleum oils with solid adsorbent materials by using adsorbents higher refining activity for solvent refined oils.

Another object is to provide a method oi treating solvent refined petroleum oils with adsorbents such as claysand the like wherein the adsorbents have a greater refining activity than in their conventionally used fresh state and wherein said adsorbents may be indefinitely regenerated to high efiiciency.

A further'object is to provide a commercially feasible method of treating solvent refined petroleum oils with'adsorbent materials such as clays and the like which have been reclaimed from discarded petroleum filter materials.

Still another object is to provide a method of treating solvent refined petroleum oils with adsorbent materials such as clays and the like wherein the adsorbents do not sufier successive degradation in eificiency with successive regenerations.

The present invention comprises subjecting.

yfinely divided porous materials which have carbonaceous petroleum matter associated therewith to a carbonizing treatment whereby the petroleum matter is converted to a deposit of activated carbon on the porous material and then treating solvent refined petroleum oils with the carbonized material. While it may be found desirsble at each activation treatment or at intermittent treatments to burn on part of the petroleum matter or carbon associated with the clay or other porous material, the essential feature is that at each treatment at least a sufiicient portion of the petroleum product associated with the clay is carbonized on the clay to a highly. active carbon deposit, to give the clay an enrefining activity. y

We disclose in our oo-pending application Serial No. 275,672 filed May 25, 1939, the advantages of carbonizlng petroleum refining clays in general. and point out therein that contrary to the conventional regeneration processes of today which regain the carbonaceous impurities is a complete evil which clogs the porous structure of the adsorbent and which must be burned ofi. our carbonizing process makes use of at least a portion of this carbonaceous impurity by converting it to an activated carbon deposit on the clay. Our present invention is based on our specific discovery that carbonized clays and the like have a refining activity for solvent refined oils that is far superior to even its own activity for other oils.

It must be admitted, of course, that activated carbon is a known adsorbent material. However, as pointed out hereinabove, despite the long recognized disadvantages and wastes of the conventional clay regeneration methods, the long desire for improvement and the many attempts to improve, it has never occurred to the petroleum industry that the petroleum oil impurities deposited on their clay adsorbents could be successiully and feasibly converted to activated carbon which would give the clay even as efilcient activity as it would have by completely burning off the impurities and it has certainly never occurred to the art that such carbonized clays had far greater activity for solvent refined oils than for acid-treated oils. Accordingly, the art goes on today regenerating the granular clays such as used in the percolation methods in the manner set forth above, resigning itself to the decreased eificiencies and discarding to waste enormous quantities annually. The finely pulverized clays used in contact processes, although not so commonly used, are as stated above generally discarded to waste after the first use with no attempt to regenerate since a process considered feasible for their regeneration has not been suggested.

The method of regenerating the clay for our process necessitates but little change in the present burning methods and means for regenerating clays. While other methods might be devised which incorporate the principles oi our invention it is preferred to operate in a manner closely analogous to present burning method thus increasing the commercial acceptability of the process.

Accordingly the regeneration may be carried out by heating, for instance, spent petroleum filter clays under the well known clay burning conditions of time, temperature, etc., but with control of the atmosphere contacting the clay in such manner that the regenerated clay carries an activated carbon deposit rather than having all the impurities burned oil. The carbonized clays thus produced are used in the conventional methods for treating solvent-refined oils with clays.

It has been found that the temperature of our carbonizing regenerating process may be varied over a considerably wider range than is desirable in the clay burning regeneration methods now being used. Thus in our regenerating process the temperatures required for destructive,distillation oi the adsorbed petroleum products may vary from that necessary to provide incipient distillation up to thatwhich will be damaging to the clay under the circumstances. Inthe conventional regenerating methods wherein the impurities are burned from the clay an extremely close temperature control should be maintained as otherwise inefiicient regeneration or damage to the clay results. The temperature for clay,

iectei, for instance, within the range of about 90045QU" F. with equal success. This is of itself a distinct advantage since there is less lance of damaging the clay. time of heating varies from a few seconds at 1500" F. to several minutes at 1000 F.

The important feature in regenerating by the present process is proper control of the atmosphere in the regenerating or activating zone. The essential feature is to sufficiently restrict the amount of air or other carbon oxidizing gas in the zone that complete combustion or oxidation of the petroleum products will not occur. It has been found that carbonization takes place both in the complete absence of air or other carbon oxidizing gas and also to the presence of limited amounts of air provided the The optimum 7 quantity -is insufficient to oxidize the activated carbon from the clay. Thus in carrying out the carbonization the heating zone may be com- I .the removal of hydrocarbon vapors and reduces the rate of carbon build-up on the c ay. For some oils it appears carbonizing in the presence ber).

for controlling the amount of air or other combustion supporting gas admitted to the carbonizing zone. It is believed, however, that in any commercial set up it will be found desirable to do a certain amount of burning as well as carbonizing. Accordingly it is preferable to employ one of the Payne apparatuses as then the'one apparatus may be used for both the burning and the carbonizing. Otherwise; if it is desired to obtain the advantages in burning that may be given by the Payne apparatuses separate kilns must be used for the carbonizing and the burning.

A considerable amount of research, experimenting and testing has been done in developing and establishing the present invention. In order to clearly establish the surprising improvements which the present invention makes over the present conventional regeneration methods a substantial amount of data will be set forth herein. All of the activity tests are tests of the decolorizing efliciency of the clay by the percolation method and the values are based on fresh clay as being 100%. The number of the clay indicates the number of times it has been regenerated (by conventional burning or the present carbonizing as indicated after the num- Various petroleum stocks were used in the tests and they are as follows:

Stock Sp. Gr.

8. 'U. viscosity Crude source Treatmetugflggfore fli- Do. Cblorex (solvent rel.)

of steam gives slightly better results, however, in general, reactivation is approximately the same for all the above carbonizing methods.

In practice we prefer to carry out our regenerating process in apparatuses such as disclosed in the two co-pending applications Serial Number 270,942 and Serial Number 279,008, filed April 29, 1939, and June 14, 1939, respectively, of John W. Payne wherein the clay is passed through the regenerating zone in close proximity to a liquid heat transfer medium. These apparatuses have several construction and operating advantages over other known regenerating kilns. In regenerating clays by burning as is now commonly done in the art an extremely close temperature control should'be maintained and for such regenerations the above mentioned Payne apparatuses are highly advantageous on this point alone. Furthermore the apparatus disclosed in Serial Number 270,942 is well suited for regenerating the finely divided contact clays as well as the granular clays, the clays being carried through the apparatus suspended in a gaseous medium. However, as mentioned herelnabove the close temperature control of burning regenerations is not necessary in the present carbonizing process. Accordingly insofar as the degree of reactivation is concerned the present process may be carried out in other apparatuses such as the baffled vertical flue, rotary kiln or multiple hearth kilns now in common use in the industry with equal success, the clays being passed through these kilns in the same manner in which they are under burning methods, it being understood, of course, that in any apparatus used appropriate provision must be made It will be recalled that one of the principal objects 01' the present invention was the regeneration of clay to a higher activity than is obtainable by present methods in common use. That such object has been attained to a high degree by the present invention can be seen clearly from the following data:

TABLE I COMPARATIVE YIELDS mom BUBNED AND Canaomzmn CLAY Percent percolation eflicianc (without nap tho dilution) Stock may Multi is heart Carbonburned ized clay clay A Fresh burned 100 No. 10 55 217 Av. No. 1 to No. 10. 66 193 B Fresh 100 100 N0. 10 50 250 Av. No.1to No 1 631i 246 C Fresh b 100 100 0. 9 52 Av. No. 1 to No. 9.- 66 131 D Fresh burned 100 100 No 65 220 H Fresh burned 100 100 No. l 88 117 No. 2 93 No. 3 66 130 from the flble. With all the oils treated the.

carbonized clay showed marked improvement these oils far surpassing even Carbonization No.

' Carboniaation No.

over the corresponding burned clay. It is needless to point out the commercial advantage of such increased activity. .It will be noted that on some of these oils the activity of the carbonized clay goes even above 200%. Furthermore that clays which have been burned 10 times and upon another burning regeneration have an efllciency around 50, at which time they would usually be discarded to waste, may be regenerated by our TABLE II Sonvmvr Rnrmnn 011:,

" inabove, under present day conventional burning regenerations the clays are thrown away after 7 to 10 regenerations. From the above table it is seen that at 7 to 10 regenerations by our process the efficiency of the clay is still at a very high level and that the efliciency stays at the high level upon further regenerations. Theoretically clays could be regenerated forever by our process, however, by present methods and means of regeneration there is about a 2% mechanical loss of clay from handling with each regeneration. Therefore the clay is lost through handling before it reaches a point at which regeneration is not feasible. As the loss is about 2% per regenera- Stock A (i) perco- Btock B (2) percolated to 65 Lov. la

ted to 75 Lev.

Clay, methodoi reactivation Straight 83 Straight Solution Stock (3) tedto Carbonization No. 1

(fresh clay) Carbonization No. 2. Carbonization No. 3 Carbonization No. 4. Carbonization No. 6

Carbonizaticn No. Carbcnization No. 8 Cerbonization No. Carbonization No. Carbonizstion No. Oarbonization N o. Carbonization No. Carbonization N 0.

Average Acre Tamra!) Srocxs Stock E (6) percolated to 190 Lov.

Solution Stock 0 gel-minted 1.2 Lov. straight Stock F (4 Straight Cerbonisation No. l

(of fresh clay) Cerbonization No. 2. Carbonization No. 3. Carbonization No. 4 Carbonization No. 5. Carboniaation No. 9. Carbonimtion No. 8. Carbonisation N0. 9. Carboniaation No.10.

Average (a) Solution consists oi 50% (vol.) oil and 50% (vol.) oi naphtha. Yields are based on reduced oil.

(1 Initial color 105 Lovibond (14" cell).

(2 Initial color 120 Lovibond (54" cell).

(3) Initial color 95 Lovibond (34" cell).

(4) Initial color 15 Lovibond (34" cell (5) Initial color 3.6 Lovibond 0t" cell). (6) Initial color (750 Lovibond (34" cell).

Thus while our carbonized clays may be used with advantage on any oils, it is apparent from the above data that such clays have a tremention this would mean the clay could be regenerated in practice about 50 times.

One of the most surprising and important features of the present invention is the fact that clays which have been regenerated by conventional burning methods until their efiiciency is so low it no longer pays to regenerate them, i. e., they have been burned about 10 times and their efiiciency is around 50 or may now be subjected to our carbonizing treatment and their efiiciency becomes greater than the fresh clay. More surprising still is the fact it is possible to reclaim these burned clays that have been thrown away. For instance, it is possible to bring in discarded clays off the dumps at the refinery which, as explained above, have been thrown away because of their low efficiency and bonize these synthetic granules and use them in percolation treatments of solvent refined oils. The following data illustrate the type results that may be obtained with reclaimed discarded petroleum filter clays:

TABLE n1 CLAY Method of reactivation Stock A Stock B lated lated 6 Lev. to 76 Lev. straight ltrsight Gar bonimtion No. 1 of No. refinery day. 140 v 164 Car boniution N o. 2 0! No. 10 refinery clay. 149 248 Cerooniution N o. 3 of N o. 10 refinery clay. 129 201 Car boniution N o. 4 oi N o. 10 refinery clay. 131 170 Car aoniretion No. 6 0! No. 10 refinery clay. 125 124 Carbonizstion N o. 6 of No 10 refinery clay. 139 123 Carbonintion No. 7 cl No. 10 refinery clay. 149 101 Carbonirntion N o. 8 of No. 10 refinery day. 1133 2'30 Carbonintion No. 0 of No. 10 refinery clay- 163 230 Carboniration No.10 oi N o. 10 refinery clay. 150

Average 146 100 The tremendously important commercial aspects of all the features 01 our invention should be readily apparent from the foregoing data. It is obvious from the data that very substantial savings may be made over present processes.

Since it may not be apparent from the data it might be well to state that carbonized or burned clays which have been used for refining acid treated oils may be subjected to a carbonizing treatment and it is then used for refining solvent refined oils and it is found that their activity for the solvent refined oils is of the extremely high nature 01' the clays shown in the tables.

The physical characteristics and oxidation stability of oils percolated through our carbonized clays are approximately the same as those of oils percolated to the same blend color through conventionally burned clays as is shown by Table IV.

of Duo Sol treated oil through our carbonized clay. however, results in stream colors which.

darken by progressively smaller color increments thus resulting in larger filter yields. The stream colors are approximately the same for percolation of acid-treated oils through either burned clay or carbonized clay. (The percolation yields of Duo Sol refined oils are considerably higher for straight percolation than for solution percolation, but the percolation yield of acid treated oils is approximately the same.) The color of the wash all from carbonized clay is about the same as that of normally burned clay.

A further advantage or the present process results from a more eillcient regeneration that is possible. Because of this more efllcient regeneration, smaller'inventories oi clay are required and consequently less capital investment. Moreover, the extensive classifications and bin men ities required by present day conventional methods of regeneration may be eliminated. Under the present process the clay need only be separated into two classes, that is, fresh clay and revivified or carbonized clay.

While the invention has been described hereinbefore principally with respect to regeneration of spent clays, the invention may be made use oi to increase the activity of fresh clay. Thus fresh clay may be dipped or otherwise coated with a suitable petroleum oil and then subjected to our carbonizing process, thereby giving it an activity which is greaterthan its original activity.

The invention has been described in detail with respect to treatment of petroleum refining clays. -While clays, and particularly Iullers earth, are by far the most commonly used solid adsorbent means for refining petroleum today, other solid adsorbent materials such bauxite, silica gel, etc., are used to a limited extent in 40 place of clays. It is understood that the present TABLE IV Paorlums or Ous PIBCOLATED Tnaouoa Caneomznn Arm PLANT BUB-Nib CLAYS Color 8 U. V.

Stock Type of clay V. I

Lovibond Sto 0 o mu) 100 F 210 r.

i A Fresh burned clay 66 2 A No. 7-10 plant burned clay 55 62 3 A Fresh clay burned after 11 carbonizations 52 46 1 4 A Fresh clay after 2 carbonizations 55 62 5 A Fresh clay after 6 carbcnizations 56 60 677 67. 3 96 6 A Fresh clay after 11 carbonizationmnn B5 52 570 67. 3 06 7 A Fresh clay alter 14 carbonizations. 56 64 580 67. 7 96. 8

8 A No. 10 plant clay alter 2 carbonizetions 58 60 9 A After 4 carbonizations 55 60 578 67. 2 96 10 A No. 1-10 plant clay aiter 1 carbonlration 57 67 571 60. 0 95. 4 11 A Fresh clay after 1 carbonization without steam-.. 67 69 12 A Fresh clay after 4 carbonizatlons without steam 56 54 676 67, 3 9e. 1 13 B Fresh burned clay 72 87 1040 00. 6 95. 6 14 B No. 5-10 plant burned clay 73 91 1042 90. 4 95. 8 16 B Fresh clay burned after 15 carbonizations 76 81 973 87. l 95. 6 10 B Fresh clay after 2 carbonizatlons 75 91 1058 01. 6 96. 6 17 B Fresh clay aiter 10 carbonimtions 76 93 1063 01. 4 95. 6 18 B No. 6-10 plant clay after 1 carbonization. 76 79 1002 88. 4 95. 1 19 B No. 10 plant clay after 2 carbonizatmns-. 76 85 10M 91. 2 95. 3 20 B After 4 carbonizations 75 81 998 88. 2 05. 8 21 C 12. 5 8. 0 22 O 12. 5 8. 0 25 C 15. 0 13. 5 I O 12. 5 0. 0

In addition to the advantages set forth hereinabove, it has been found that certain other advantages are obtained by using our carbonized clays in the refining of solvent refined petroleum oils. It has been found that when 9. Duo Sol treated oil is percolated through burned clay, the color of the filter stream becomes darker by relatively constant color increments and is invention is applicable to these other solid adsorbent refining materials that may be used in place of clays, and, in fact, any finely divided porous material which does not have a deleterious chemical action of its own may be used as the carrier for the activated carbon deposit.

This application is a continuation-in-part of our co-pending application 3. N. 275,672 filed soon darker than the charge oil. Percolation May 25, 1939.

. um carbonaceous matter.

, 2 In a method of refining solvent refined petroleum oils with porous adsorptive materials wherein said adsorptive materials are used for 1 refining petroleum oils until contaminated with petroleum matter and are then regenerated for. I reuse. the improvement which comprises regencrating said contaminated adsorbents by carbonizing said petroleum matter on said adsorptive "material to form an activated carbon deposit thereon and then refining solvent refined petroleum oils with said carbonized adsorptive ma- I I l 3. a method of refining solvent refined petroleum oils with finely divided filter clays wherein said filter clays are used for refining petroleum oils until contaminated with petroleum matter and are then regenerated for reuse, the improveiment which comprises regenerating said contaminated clays in their finely divided stateby carbonizing said petroleum matter on said filter clays to form an activated carbon deposit thereon and then refining solvent refined petroleum oils with said carbonized filter clays. v g 4. The method of increasing the petroleum refining efiiciency oi filtering processes for solvent a refined petroleum oils with materials such as clays and the like which comprises coating said of refining solvent refined pe- 7. The method of increasing the efiiciency oi a clay percolation filtering process ior solvent refined petroleum oils which comprises regencrating the granular percolation clay when it becomes undesirably contaminated with petroleum matter by subjecting the clay to a destructive distillation process in the presence of steam at a temperature between about 1000 and about 1500 F. to produce" an activated carbon deposit on said clay from said petroleum matter and then filtering solvent refined petroleum oils through said carbonized clay by percolation.

8. In a process for filtering petroleum oils with adsorbents such as clays and the like wherein the filtering adsorbents are periodically regenerated as they become contaminated with petroleum matter the improvement whereby the filtering adsorbents are always regenerated to desirable activity which comprises regenerating the filtering adsorbents by carbonizing said petroleum matter on said adsorbents in an atmosphere having a sufiiclently restricted-amount oi carbon oxidizing gas to produce an activated 'carbon deposit on said filtering adsorbents from said petroleum matter and then filtering solvent refined petroleum oils with said carbonized adsorbents.

9. The method of filtering solvent refined petroleum oils with regenerated adsorbents such as clays and the like which have a higher efilciency than'the adsorbent in its'iresh state which oomprises filtering said solvent refined oils through filter materials-with petroleum carbonaceous matter, 'carbonizing saidpetroleum matter on said filter materials to form an activated carbon deposit thereon and then refining solvent refined petroleum oils with said-carbonized filter materials.

5. The metha 'oiincreasing the petroleum re- :fining efilciency of'illtering processes for solvent refined petroleum oils with finely divided adsorbent materials such as clays and the like which comprises regenerating spent adsorbents in their finely divided state which are contaminated with petroleum matter from a previous filtering process by carbonizing said petroleum matter on said adsorbent in an atmosphere having a sufiiciently restricted amount of carbon oxidizing gas to produce an activated carbon deposit on said adsorbent from said petroleum matter and then fil- [tering solvent refined petroleum oils with said carbonized adsorbents.

6. The method of increasing the efilciency of delay percolation filtering process for solvent refined petroleum oils which comprised regenerating the granular percolation clay when it becomes undesirably contaminated with petroleum matter by carbonizing said petroleum matter on said clay at a temperature between about 1000 and about 1500 F. in an atmosphere having a sufficiently restricted amount of carbon oxidizing gas to produce an activated carbon deposit on said clay from said petroleum matter and then filtering solvent refined petroleum .oils through said carbonized clay by percolation.

adsorbents which have been regenerated by having petroleum matter'carboniaed thereon to iorm an activated carbon deposit which gives said adsorbents a greater filtering efiiciency for the solvent refined petroleum oils than that oi the adsorbent in its fresh state.

10. The method of filtering solvent refined petroleum oils with discarded petroleum filter clays which have been reclaimed in such manner as to possess a higher efiiciency than possessed in their fresh state which comprises carbonizing petroleum matter on said discarded clays to form an activated carbon deposit thereon and then filtering said solvent refined petroleum oils through said carbonized clays.

11. A method of refining solvent refined petroleumoils with adsorbents which comprises refining said solvent refined oils with contact clay carrying an outer layer deposit of activated carbon produced from petroleum carbonaceous mat-' leum. carbonaceous matter, which outer carbon layer is in sufiicient amount to give the particles a decolorizlng eificiency for solvent-refined petroleum oils that is substantially above that possessed by the inorganic particles alone in their fresh state.

THOMAS P; SIMPSON. JOHN W. PAYNE. PETER D; VALAS. 

